Propulsion system for underwater divers



Dec. 4, 1962 .1. H. ANDRESEN, JR 3,065,638

PRoPULsIoN SYSTEM FOR UNDERWATER DIVERS De@ 4, 1952 J. H. ANDRESEN, JR 3,066,638

PROPULSION SYSTEM FOR UNDERWATER DIVERS 2 Sheets-Sheet 2 Filed Sept. l, 1960 United States Patent Oiitree 3,065,638 Patented Dec. 4, 1952 This invention relates to a propulsion system for underwater divers, and more particularly relates to a novel propulsion system incorporated in self-contained underwater breathing apparatus for the divers.

Underwater breathing apparatus of the self-contained type is known as scuba. Conventional scuba of the open circuit type uses compressed air (or mixture of oxygen and helium). The compresesd air is contained in one or more cylindrical tanks `at 2000 to 3000 p.s.i. pressure. The tank or tanks are fastened to the back of the diver. The tank air is reduced in pressure and metered at the local water pressure of the divers depth. A one or two stage demand regulator is employed.

The regulator operates through the slight reduction in pressure (eg. 1 or 2 inches of water pressure), in the mouthpiece or face mask. The dived eects the regulator air release by his act in attempting to inhale. The regulator throttles the compressed air in the exact amount thus called for by the diver, in a manner well known in the art. When the pressure in the air storage cylinders is down to about 300-500 p.s.i., the diver surfaces, and the tanks are replaced.

The diver equipped with scuba uses rubber tins on his feet to aid in his underwater swimming and locomotion. Where a large underwater area is to be explored, the eitort in his swimming is relatively great. Further, his resultant air consumption is high. To alleviate this eort `and problem, propulsion aids are often used by the diver. One such propulsion device is a small battery-operated torpedo-like submarine that pulls the diver. Another is an underwater sled or hand-held vane towed by surface craft.

ln accordance with my present invention a small compressed air operated motor is -attached to the diver. The compressed air that drives this motor is the same air from the scuba tanks which the diver subsequently breathes. The air motor rotates a water propeller. The energy in the compressed air supply is thus used to propel the diver each times he takes a breath. In the conventional scuba this energy is wasted through throttling in the pressure regulator. The diver still may wear tins on his feet for maneuvering, and to aid in propulsion. f

lt is accordingly an object of the present invention to provide a novel propulsion system for scuba divers.

Another object of the present invention is to provide a novel propulsion system incorporating an `air motor driven by the -compressed air of a scuba equipped diver.

A further object of the present invention is to provide a diver propulsion system incorporated in a scuba that is activated upon the ldivers breathing of the supplied air.

Still another object of the present invention is to provide a diver propulsion system using an air motor driven by energy of the compressed lair in a scuba as it is reduced in pressure for the diver for his breathing.

These and other objects of my invention will become more apparent from the following description of an exemplary embodiment thereof, illustrated in the drawings, in which:

FIGURE l is a diagrammatic assembly of an exemplary form of the invention system, incorporated in a scuba.

FIGURE 2 illustrates a diver using the scuba assembly of FIGURE l.

FIGURE 3 is a diagrammatic representation of a modified form of the invention hereof.

The compressed air cylinder 10 used for diving typically holds 70 cubic feet of air measured at sea level pressure, condensed as to atmospheres at the start of a dive. Such tanks `are used at 2000 to 3000 p.s.i., as aforesaid. A diver breathes at the rate of approximately 1 cubic foot per minute, regardless of the ambient hydrostatic pressure. At 33 foot depth (2 atmospheres), with the rst stage of a regulator set at 5 atmospheres, an energy rate of 9.3 H.P. is available. This is derived directly:

When the tank is expended to only 15 atmospheres, the energy rate at 33 foot depth is, correspondingly, 0.65 H P. This is derived by:

. The air is drawn intermittently from the tank 10, and the compressed air operated motor 11 is a relatively small one. The motor 11 structure is secured to the neck 10' of tank 10, through which the compressed air flows into the motor. A propeller 12 is driven by the motor 11. Even with a power conversion efficiency of only 25%, from air pressure reduction to propeller propulsion, the resultant power is adequate to drive the diver at greater than normal swimming speed even at the lower tank pressure. However, two or more tanks (10) may be paralleled, in a conventional manner, to extend the duration of the dive. i

Pneumatic motor 11 is preferably of the positive displacement type. `lt may be one of several known compressed air motor constructions. 'Its displacement in the exemplary system is 0.5 to 1.0 cu. in. per turn of its output shaft 14. Propeller 12 is secured ydirectly to motor output shaft 14 in the exemplary embodiment. `The use of air herein, and in the claims, is to be understood to be generically inclusive of other gases used.. as a combination of oxygen and helium.

The output or air exhaust duct of motor 11 is fed into a reducing valve 15. Reducing valve 15 is proportioned to reduce the incident (tank) pressure to an absolute pressure somewhat higher than that at the lowest depth the ydiver intends to go to. As an example, for a lowest diver descent of 60 feet, the pressure output of reducing valve 15 is set to 5 atmospheres. The output from the low pressure side of valve 15 is led through hose 16 to air demand regulator 17. Hose 16 is at intermediate pressure.

rihe air demand regulator 17 may be a conventional type that regulates the flow of air supply to the diver. Regulator 17 does not release a continuous flow of air, except on demand. The inhaling and exhaling occurs through rubber mouthpiece 20. enters regulator 20 at a control valve 18. An aperture Z1 admits ambient water pressure against control diaphragm 22, coupled to control valve 18. A check valve 23 leads exhaust air to output end 24.

The propeller has a guard 25 about it, anchored on motor 11. Each time the diver inhales air through mouthpiece 20, control valve is opened to admit air from intermediate pressure hose 16. This causes air pressure from tank 10 to expand through air motor 11 and pass through the first stage reducing valve 15. The motor thereupon operates `to rotate propeller 12. The result is a thrust b (see FIGURE 2). This thrust b reacts to move the tank 10 attached to motor 11, reversed into the swimming direction a. With the tank 10 strapped to `the diver, the forward (reaction) propulsive thrust (-b) is added to his forward drive in the direction a. This added'thrust (-b) The air from hose 1'6" prevents fatigue and increases the range of the diver for a given supply of air in tank 10.

In using the invention system the diver has the tank (or tanks) strapped on his back, as shown in FIGURE 2, with the propeller directed rearwardly of the divers swimming direction a. The diver is attired with a mask 26 and foot tins 27, 27. As the diver attempts to inhale, the diaphragm 22 of demand regulator 17 moves inwardly, opening control valve 18 through the mechanical linkage 28 to the intermediate pressure in hose 16. As long as the diver attempts to inhale, air flows through the control valve 1S and into his lungs through mouthpiece 2t). When he exhales, the higher pressure created in the regulator 17 closes the control Valve and opens the check valve 23, letting the expiredl air escape in the water.

When the air (thus breathed) flows out of hose 16, the intermediate pressure at the output of the first stage reducer valve drops. Valve 15 is similar to the second stage regulator 17 in principle, except that a spring holds its control valve open until a predetermined pressure is reached in the output part. When the output pressure of valve 15 (at hose 16) is thus lowered through a breath taken, the high pressure air from the motor (11) exhaust ows through the valve 15 to hose 16. This air, coming through the air motor 11 rotates its shaft 14 to which the propeller 12 is secured. The cylindrical shield 25 increases the effectiveness of propulsion.

lThe speed of a body in water is approximately proporF tional to the cube root of the net propulsive power applied to it. The ratio of speeds increment derived from the invention system from a full compressed tank (10) and one depleted is the ratio of the cube roots of the corresponding power application to the propeller 12 (assuming reasonsably equivalent power conversion efficienCy). As derived above, the available energy rate to air motor 11 by the invention system is 9.3 H.P. with the tank (10) at 150 atmospheres; and 0.65 H.P., at 15 atmospheres. Hence the speed range provided by the invention is 9.3 to 0.65=2.4 to l. Such speed ratio is not excessive and very useful in practice. Further the waning power supplement provides the diver with a valuable warning when his tank pressure is getting low.

A more continuous thrust may be arranged, than the intermittent one described. Smoothing of the propulsive impulses can be obtained by causing air to ow continuously through the mouthpiece. Towards this end a manually operated button 28, indicated in dotted lines, eX- tends through aperture 21 and is used to depress diaphragm 22 of regulator 17. In such operation the air is breathed in during inhaling and wasted through valve 23 with the exhaust air during exhaling.

An alternative method is to use a second compressed air cylinder in the underwater diving, exclusively for propulsion. Such system affords the propulsion for the diver, under manual control of a valve corresponding to the second regulatory stage as described hereinabove. The motor 11 and propeller 12 are a reciprocating air motor system 30 to effect a pulsating jet to provide linear propulsion to the diver. System 30l comprises a cylindrical housing 31, at one end (32) of which the water input lies. This end 31 also is attached to the rear of the air tank (10) or to the diver. The reciprocating motor system 30 has rubber tiapper valves 52, 52 on a conical piston 33 that pumps the input water in a pulsating mode to water out at end 34, and effect the propulsive force to propel the diver in the opposite (reaction) direction.

The exemplary system 30 contains a reciprocating piston type of air motor 35, the end coupling 36 of which is coupled by a line (37) to the air tank (10). The input bore 38 connected to an automobile tire-type valve 39 that in turn abuts the center of a snap spring 40 used with the second tank in the manner of the system shown in FIGURES 1 and 2; as will now be understood by those skilled in the art.

A modication is feasible wherein the intermediate air pressure can be regulated to some higher pressure such as l0 atmospheres, and the motor (11) placed in the line between the first and second stages previously described. The propulsive force by such arrangement is not as high initially as by the previous system described. However, the pressure remains more sustained and uniformy as the tank air is depleted.

The propulsive means: rotary motor (11) described hereinabove in conjunction with screw propeller 12 (FIG- URES l and 2), may take other forms Without departing from the present invention. FIGURE 3 illustrates a rod 41 coupled to snap spring iti operates the piston 42 that is connected to the apex 43 of the conical piston 33. A coaxial restoring spring 44 for the piston 42 coacts in sustaining the reciprocating action as will be understood by those skilled in the art. An over-pressure relief valve 45 and an O ring seal 46, the pump motor 35 constitute the basic components. A threaded opening 47 and bore 48 communicates between the chamber 49 of the motor 35 and a line 50 (shown in dotted lines) to the second stage regulator (as 17), at its mouthpiece.

The conical piston 33 is reciprocatably supported in housing 31 through a rubberized fabric seal 51. The nozzle 53 at the exit end (34) of housing 31 is suitably proportioned for the propulsive jet action of the water reciprocatably ejected through the flapper valves 52, 52 by the piston 33. A smooth linear propulsive force is thus supplied to the diver by the air drive reciprocating system 30.

Although the invention has been set forth in conjunction with exemplary embodiments thereof, it is to be understood that modifications may be made within its broader spirit and scope as dened in the following claims.

I claim:

1. Underwater propulsion apparatus of the character described comprising a high pressure air tank, an air motor with an air input connection coupled to the tank. water propulsion means driven by said air motor, and pneumatic means extending from said air motor for passing air from said tank thereto to effect its driving, said air motor being of the reciprocatory type, said water propulsion means including flapper valves to effect linear propulsion upon reciprocatory displacements by said motor.

2. Underwater propulsion apparatus as claimed in claim 1, in which said pneumatic means includes a reducer valve in connection with said motor.

3. Underwater propulsion apparatus of the character described comprising a high pressure air tank with an air output connection, an air motor with an lair-input connection coupled to the tank air output connection, said air motor -being physically securable with said tank, water propulsion means driven by said air motor in a propulsive direction substantially parallel to t-he tank longitudinal axis, and pneumatic means extending from the air output connection of said lair motor responsive to breathing of a diver lfor passing air from said tank through said air motor to drive said propeller and contribute propulsion to an underwater diver wearing the apparatus in said propulsive direction; both said air motor and said water propulsion means being of the reciprocatory type, said water propulsion means operating on water ambient about the diver.

References Cited in the tile of this patent UNITED STATES PATENTS 2,722,021 Keogh-Dwyer Nov. 1, 1955 FOREIGN PATENTS 40,246 Germany u July 29, 1887 

